German Patent Application 38 31 196 describes an electromagnetically operable valve which has a valve needle that is axially moveable in a through-hole of a valve-seat support. The valve needle is formed of a cylindrical armature, a spherical valve-closure member and a tubular or sleeve-shaped connecting part connecting both structural elements to one another. The connecting part is produced from a flat sheet metal which is subsequently rolled or bent until it assumes a cylindrical, sleeve-like shape. In this form, the connecting part has a slit extending over its entire axial length which can run either axially-parallel or at an angle to the longitudinal valve axis. The two end faces of the sheet metals used, running in the longitudinal direction, lie opposite each other with a constant clearance forming the slit between them. When producing a fixed joining between the connecting part and the valve-closure member by applying a welded seam using a laser (continuous wave laser), disadvantageous sink marks develop at the relatively broad slit. In this context, a sink mark is an area at which less material is available for fusing, and at which material consequently falls inwardly. As a consequence, at such a location the welded seam has a dent-shaped, concave depression which represents a certain disturbance of the welded seam. Although the laser ray is not masked out when sweeping over the slit, the welded seam may even have a break in the area of the slit.
German Patent Application No. 40 08 675 described an electromagnetically operable valve, in which the valve-closure member is attached to the connecting part by a welded seam, the welded seam being interrupted at least in the area of the longitudinal slit, or even additionally at further spots in the circumferential direction.